I'm not an expert at crochet, but I would hold two pop tabs together, so that they are one on top of the other so the two holes would be aligned, and you could simply stick the crochet hook through, draw up the wire, and pull it through the loop to chain them together. Do the same in the next holes. Then you'd grab two more pop tabs, and continue chaining them together. When you are done, you can open up the two sides and lay them flat. On one side would be the crochet chain, on the other, the loop, like what you see in the picture.
Kind of like how you'd crochet the squares of a blanket together.
Does that make sense?
Oh, and you'd want a finer gauge metal wire, like jewelry wire.
If you try this, post some pics so we can see!
ETA: On closer inspection, I agree that it looks like some kind of stretchy silver novelty thread too.